I've never thought to use a parsing tool at all. What I would consult if I felt insecureabout these particular forms is the paradigms in Smyth's grammar; I would expectthe forms for ἐπερωτάω to follow strictly the paradigm of alpha-contract verbs.

Why Perseus doesn't work for these forms I don't know, unless it's that these forms simply do not appear in any of the texts in the Perseus corpus -- but I don't know whether the parsing tool is supposed to fit all regular verbs or not.

Another resource for verb forms you might like to know about is Kalos software at:

It has downloadable programs for Windows and a .jar platform-independent one that will doverb analysis and produce charts. The most recent version is kalos 4.4, released in Januaryof 2011. Kalos will do a number of different things, including definitions in English, French,and Spanish.

For irregular verbs, I would always check the initial section of LSJ entries for verbs, where all forms that are unpredictable are listed.